Patients are often treated for diseases and/or conditions associated with a compromised status of the patient, for example a compromised physiologic status. In some instances, a patient may report symptoms that require diagnosis to determine the underlying cause. For example, a patient may report fainting or dizziness that requires diagnosis, in which long term monitoring of the patient can provide useful information as to the physiologic status of the patient. In some instances a patient may have suffered a heart attack and require care and/or monitoring after release from the hospital.
Chronotropic incompetence (hereinafter “CI”) can be a debilitating condition associated with high mortality and morbidity. Chronotropic incompetence can be defined as the inability for a patient to elevate heart rate to 85% of the age-predicted maximum heart rate (hereinafter “APMHR”) level during exercise in a clinical environment. The determination of the ability of the patient to raise HR can be done by subjecting a patient to exercise in a clinic to elevate the patient HR, for example with a treadmill in a clinic.
Work in relation to embodiments of the present invention suggests that known methods and apparatus for determining CI may be less than ideal. At least some of the known methods and apparatus test the patient in a clinical setting and may not determine the presence of CI when the patient is located remote from the clinic, for example located at home. Although successful in determining the presence of CI in a clinical setting, current methods that rely on a controlled environment such as a treadmill in a clinic may not be well suited to determine CI when the patient is located remote from the clinic. For example, in at least some instances the patient may be somewhat frail and not well suited to exercise on his or her own. Also, current methods of determining the maximum HR of the patient assume that the patient is able to exercise the level of his or her capacity when the maximum HR is measured, and in at least some instances such an assumption may not be appropriate, such as for patients with respiratory and cardiac diseases, as well as patients with physical disability.
Another approach to determining cardiac function related to CI in a patient can be to determine the heart rate reserve (hereinafter “HRR”) of the patient, in which the HRR is determined with the resting HR of the patient. However, in at least some instances it can be difficult to determine the resting HR of the patient in the clinic. In at least some instances, measurements of a patient in a clinic can be nervous and the heart rate can be elevated, for example with white coat syndrome, and the patient may receive an incorrect diagnosis in at least some instances. Further, at least some of the present methods of measuring HR remotely may not provide appropriate data to determine the resting HR when the patient is located remote from the clinic.
Therefore, a need exists for improved patient monitoring. Ideally, such improved patient monitoring would avoid at least some of the short-comings of the present methods and devices.